Polymer blends that exhibit flexibility in addition to high strength and resistance properties are of significant commercial interest. Such blends have been formed in the past by uniformly mixing an elastic component with a thermoplastic polyolefin such that the elastomer is intimately and uniformly dispersed as a discrete or co-continuous phase within a continuous phase of the polyolefin. Vulcanization of the composite crosslinks the components and provides improved temperature and chemical resistance to the composition. When vulcanization is carried out during combination of the various polymeric components it is termed dynamic vulcanization.
Polyarylene sulfides are high-performance polymers that may withstand high thermal, chemical, and mechanical stresses and are beneficially utilized in a wide variety of applications. Polyarylene sulfides have often been blended with other polymers to improve characteristics of the product composition. For example, elastomeric impact modifiers have been found beneficial for improvement of the physical properties of a polyarylene sulfide composition. Compositions including blends of polyarylene sulfides with impact modifying polymers have been considered for high performance, high temperature applications.
Unfortunately, elastomeric polymers generally considered useful for impact modification are not compatible with polyarylene sulfides and phase separation has been a problem in forming compositions of the two. Attempts have been made to improve the composition formation, for instance through the utilization of compatibilizers. However, even upon such modifications, compositions including polyarylene sulfides in combination with impact modifying polymers still fail to provide product performance as desired, particularly in applications that require both high heat resistance and high impact resistance.
What are needed in the art are polyarylene sulfide compositions that exhibit high strength characteristics as well as resistance to degradation, even in extreme temperature environments, while maintaining desirable processing characteristics.